Final answer:
The micturition reflex involves the contraction of the detrusor muscle, relaxation of the internal urethral sphincter due to parasympathetic outflow, and inhibition of somatic motor neurons. Sympathetic neurons suppress detrusor contractions during filling of the bladder. Answer option C is correct regarding the role of stretch receptors in initiating the micturition reflex.
Step-by-step explanation:
During the micturition reflex, the correct scenario involves parasympathetic neural outflow, which causes contraction of the detrusor muscle and relaxation of the internal urethral sphincter. Simultaneously, somatic motor neurons that control the external urethral sphincter are inhibited, allowing for relaxation and urination. The sympathetic motor neurons are active during the filling of the bladder to prevent micturition, by suppressing the detrusor muscle contraction and maintaining contraction of the internal urethral sphincter. Option C, which states that 'stimulation of stretch receptors in the bladder wall sends impulses to the sacral cord' is the most accurate statement regarding the micturition reflex. This process is involuntary but is subject to voluntary override by controlling the external sphincter. Therefore, answer choice D 'all of the following answers' is incorrectly implying that both options A and B are also correct, which they are not.